The quickest way to kill head lice is to use an over-the-counter or prescription medication that destroys the lice and, in some cases, their eggs. These products will usually kill all live lice within a few days of treatment. A second treatment may be necessary about a week later. Head lice can be spread easily through contact with an infected person. Treat all infected individuals in your household at the same time to prevent a subsequent infestation.
The active ingredients in over-the-counter lice medications that can be found in most drugstores are either pyrethrins or permethrin. Pyrethrins are extracts derived from the chrysanthemum flower. They can only destroy live lice, not unhatched eggs. Use a pyrethrin-containing product according to the manufacturer's instructions found on the package. After about 10 days, you may need to re-treat the infested area to kill lice that have hatched from the eggs that remained after the first dose.
Permethrin, usually available in lotion form, is a synthetic version of pyrethrins. It must also be reused about 10 days following the initial treatment. Like pyrethrin products, permethrin lotion only succeeds in killing live lice and not lice eggs. However, it continues to kill newly hatched lice in the days following the initial treatment. Do not use this medication on children under 2 years of age.
Two prescription medications, malathion lotion and lindane shampoo, are approved by the U.S. Food and Drug Administration to kill head lice. Malathion lotion kills live lice as well as lice eggs, or nits. A second treatment can be done a week after treatment if any lice or nits remain. Malathion lotion can only be used on those over age 6. This medication is extremely flammable, so do not smoke or go near open flames or heated hair styling tools while using it.
Lindane shampoo is extremely powerful and can be toxic if misused. Therefore, it is only prescribed as a last resort when other over-the-counter and prescription medications have failed. Lindane shampoo cannot be used by pregnant or nursing women, infants, children, people who weigh less than 110 pounds, the elderly, people with seizure disorders and people with open sores or irritated skin.
Tips and Warnings
Run a nit comb (a fine-toothed comb made specifically for the removal of lice and eggs) through your hair after every treatment to catch any stray lice or larvae that may still be embedded in your hair. Flea combs that are usually used on dogs and cats will also work. Check your hair thoroughly and use the comb for up to 2 to 3 weeks after treatment to ensure you do not become re-infested. After each use, soak the comb in hot water for at least five minutes.
Vacuum or sweep your floors during and after treatment to remove any stray hairs that may contain unhatched lice eggs. Wash all sheets, blankets, pillowcases and clothing that may have come in contact with the infested persons. If any of these items cannot be washed in hot water, have them dry-cleaned. Nits may continue to live in clothing and bed sheets after the treatment has been successful on the individual; thus, it is imperative to wash all of these items.
Do not use more than the recommended amount of head lice medicine. If you're not sure how much to use or how to use the medication, check with your physician. Do not use more than one type of head lice medication at a time.